I'm assuming he will want you to bring leads that you two can potentially work on together in some fashion. 

I started the old-fashioned way, by making sure my credit/income was good and I applied for loans with banks and mortgage brokers. 

And we do the verifications the old fashion way of actually calling the employers and landlords to get the info straight from the source. 

The IRA is handled and reported in the same fashion, but instead of just focusing on the public exchanges, they can document an IRA investment into shares of privately held stock, crowdfunds, private mortgage notes and the like. 

So yes, you could incrementally "move" the Roth IRA to the Solo 401(k) in the fashion you describe.  

I'm a 31 year old jewelry designer and fabricator living in NYC.I have no experience in real estate aside from riding shotgun when I was a kid with my mom during her open houses and property showings. 

If you want to pay for a skip trace but that is usually for lists, you can do some good old fashioned Google detective work as well.

That doesn’t mean they always cooperate or do it in a timely fashion.

I have a jewelry company based in Midtown Manhattan by the diamond district.

Interior home design has it's trends just like the fashion industry, just a lot slower.